1. Field of the Invention
The present invention relates to a cutter, particularly, it relates to a cutter used when cutting such as stones.
2. Description of the Prior Arts
FIG. 5 is a plan view showing an example of a conventional cutter which forms a background of the present invention, and FIG. 6 is a sectional view taken along the line VI--VI of the cutter shown in FIG. 5, the cutter 1 includes a ring-shaped base plate 2. On the peripheral edge of the base plate 2, there are formed a plurality of projections 4 interposing slits therebetween. Furthermore, around the projections 4 on the peripheral edge of the base plate 2, a ring-shaped cutting body 5 is formed. The cutting body 5 is formed by sintering a metal powder including abrasive grains such as diamond fine particles. The cutting body 5 is formed such that a portion of slits 3 is exposed. The slits 3 serve to cool the cutter 1 with air in use.
When using the cutter 1, it is placed against an object to be cut while being rotated so that the object to be cut is cut by the cutting body 5. At this time, abrasions take place gradually on the cutting body 5 whose inner portion is exposed to maintain the sharpness of the cutter 1.
In such a conventional cutter, however, since the base plate is made of a thin plate its strength is weak. Therefore, when using the cutter there was a possibility that the base plate may bend or cutting can not be effected smoothly due to the vibration.
Also, if the thickness of the projections is made relatively thicker, the projections hardly wear in use of the cutter. As a result, the new inner portion of the cutting body is hindered by the projections to expose on the surface, thereby degrading the sharpness of the cutter.
Moreover, as the mechanical strength of the cutting body formed at the slits is weak there was a possibility to break the cutting body at slits.